Early-May northeasterlies

Highland sunshine
by Philip Eden

This contrast between North-west and South-east is least apparent during spring when southwesterly winds are at their least frequent. In May the normal pattern is reversed: the average monthly sunshine in London is 200 hours and in the Midlands just 180 hours, compared with 205 hours on the Isle of Skye and 235 hours on Tiree in the Inner Hebrides. This reflects a peak at this time of the year in the frequency of northeasterly winds which carry persistent cloud from the North Sea to eastern England and eastern Scotland, while western Scotland benefits from the shelter provided by the highlands.

The weather of the last week or so has provided a perfect illustration of these northeasterlies at work. During the first ten days of this month the sun shone for a total of 92 hours at Tiree, 80 hours at Stornoway on the Isle of Lewis, and 73 hours at Prestwick on the Ayrshire coast, while in eastern England there has been only 27 hours of sunshine at Norwich, 29 hours at Nottingham and 32 hours at Peterborough. Nor was the sunny weather confined to western Scotland; other western districts have also done well with 95 hours at Penzance, 84 hours at Aldergrove in County Antrim, and 83 hours on the Isle of Man.

As one might expect, these northeasterly winds have also had an impact on temperatures which have soared into the seventies in the western highlands, but struggled to reach the fifties along the east coast of England. Last Tuesday, for instance, the mercury climbed to 22.1C at Dalmally in the Strath of Orchy, Argyllshire, while at Loftus, near Redcar in North Yorkshire, the day's maximum was a mere 8.6C. It was even colder along the North Sea coast on Thursday when the temperature at Loftus climbed no higher than 7.7C.

The coming week will bring a return of southwesterly winds, and that means that the warmest and brightest weather will be found in eastern England - a welcome relief, no doubt, from the recent cold and gloom.